In the prior art, several examples of shoes designed to be used by a person having a walking cast are known. In these known designs, a common deficiency lies in the fact that the person using them finds it difficult to walk with a natural gait.
Some cast shoes utilize a flat bottom such as that which is disclosed in United States Patent 3,566,487. It has been found that a flat sole increases the stability of the shoe for the user but naturally results in an undesirable flat-footed gait.
As the state of the art progressed, cast shoes began to be made with a "rocker bottom" which constituted an improvement over the flat bottom designs by allowing for more of a rolling or heel-to-toe gait. Since this gait is not a natural normal gait, the rocker bottom cast shoes did not solve all of the problems which have to be solved so as to enable the users thereof to walk normally. This is because in normal walking motion, the foot rotates externally to achieve the normal "toe-off" position on the ball of the foot. This externally rotated position requires abduction of the ankle which is, of course, not possible when the ankle is rigidly immobilized in a cast. U.S. Pat. Nos. 3,584,402; 3,802,424; 4,005,704 and 4,057,056 each disclose the concept of a cast shoe having what might be termed a "rocker bottom."
Thus, a need has arisen for a cast shoe which will overcome the deficiencies attendant in prior art designs and will thus provide a cast shoe allowing the user thereof to approximate a normal gait so as to speed the rehabilitation process and aid in the patient's comfort.